266 Marsh's Monograph on the Odontornithes 
gradual atrophy of the arm resulting from disuse, the extreme 
of which is'seen among living birds in Apieryx, had proceeded 
so far in Hesperornis that it was no better provided with fore 
limbs than are the Cetaceans with hind limbs. 
The enormous development of the legs and feet, supposed 
by some writers to point to an affinity with the Pygopodes, 
Figure 6.—Restoration of Hesperornis regalis, Marsh. One-eighth natural size. 
does not really suggest any such relationship. That “ 
legs are much alike in both groups is true; but to pA a 
that Hesperornis is merely a loon or grebe with teeth, 1S 
take a very superficial view of the structural characteristics 
